I still play it now and then, mainly as a way to make myself wake up in the mornings. It’s more effective to open Fallout Shelter than hit the snooze button. I’ve gone through several vaults by now, one of which I played through to absolute capacity.

Some background: Bethesda, the company behind such games as the Elder Scrolls series (most famously Skyrim), the Doom series, the Dishonored series (and yes it’s now a series! Woo!) and, of course, the Fallout series, released the iPhone app Fallout Shelter as an aperitif before the release of Fallout 4 in November. Everyone quickly went from talking about the Fallout 4 trailer (including the most pressing question: does the dog die?) to the app in no time flat. Kotaku posted a guide with tips on how to play the game. Sci fi and fantasy author Mur Lafferty talked about how weird she feels when she makes her shelter dwellers breed.

I feel like I just failed a perception check.

The game itself places you as the Overseer of a new Vault in the Wasteland. The short of it is, nuclear war has destroyed the Earth, and anyone who was lucky got into a Vault (or fallout shelter) before the bombs dropped. Outside the Vaults, mutated beasts and bloodthirsty raiders roam the wastes. Inside the Vaults, it’s a happy and productive utopia.

Knock knock

As Overseer, you get to build up your shelter, making sure to keep up a steady supply of food and water for your Dwellers and electricity for the Vault itself. You start with a line of Dwellers at your door, waiting to take shelter. Each of them has SPECIAL skills—strength, perception, endurance, charisma, intelligence, agility, and luck. Most of them are pretty low on everything, although you might find a rare or legendary Dweller with higher scores. The traits help them with their jobs. Strength is good for power plants, perception is good for water treatment facilities, agility is good for food preparation, and so on. Don’t ask me why. Dwellers love to work, and are blissfully happy if you assign them a job that aligns with their highest skill.

Is there anything you people are good at?

You need to keep your power, water purification, and food production at a high enough level to keep your Vault running. Low power means rooms go dark and Dwellers stop working. Lack of food means health drops, and lack of pure water increases radiation poisoning. You can heal your Dwellers as long as you have the supplies, but an ounce of prevention equals a pound of cure or however that saying goes.

In order to add more rooms and upgrade your Vault, you need currency, and that means bottle caps. You can get caps by completing challenges, or by sending Dwellers out into the Wasteland to scavenge, or by forcing your Dwellers to work extra fast by rushing a room’s production. These last two have risks—Dwellers can easily die in the Wasteland, and rushing a room can cause a fire or a radroach infestation. Still, it can be worth it, since upgraded rooms produce more.

“Oh what a day! What a lovely day!”

Everything is time based. The diner, for example, produces a certain amount of food every few minutes. Adding Dwellers with high agility scores lowers that time, as does upgrading the room. Placing up to three diners next to each other merges the rooms together to increase efficiency. However, some things take a lot longer. If you put a Dweller with a high strength score in the weight room, for example, it could take twelve hours in real time for her to increase her strength to the next level. Dwellers out in the Wasteland find better loot the longer they stay out, which could mean many hours away from your base. When you call them back, it takes them half as long to come back as the amount of time they’ve spent out there, so a Dweller who has spent 6 hours in the Wasteland will take 3 hours to return with the loot.

I had to pay 300 caps to resurrect this guy.

To increase the production of your Vault and keep things running smoothly, you’re going to need more Dwellers, but once you get past the first rush, new recruits are few and far between. In the later game, you can add in a radio room that entices new Dwellers to come in from the wastes, but that can take a long time. The best thing to do is just breed your Dwellers, and that’s where things get…odd.

Putting two Dwellers of the opposite sex together in the living quarters starts off an odd courtship ritual that involves bad pickup lines, awkward dancing, and an eventual sprint into the back of the room. After a matter of seconds, the male Dweller struts out happily, while the female trudges out, hunched over and massively pregnant. It’s… a little weird, although both of them have 100% happiness for a while, so I guess they enjoyed it? The female returns to work, and the only difference in her behavior is that instead of whipping out a gun or her fists when danger shows up, she flees, waving her hands in the air and screaming. Apparently pregnant women and children are effectively immortal, taking no damage from raiders, radroaches, fire, starvation or thirst.

It was around this point that I started to feel weird. It takes a while for mothers to have their babies, and then for the babies to grow up, so I’d usually get all of the women pregnant before I closed the app for the evening. Seeing all those pregnant ladies in their matching yellow sweaters and massive bellies working happily in the power plant made me feel a little creepy, like I was running some sort of cult.

“Subjugate”

Immediate family members can’t procreate, although it can be hard to tell who is related to whom after a couple generations of breeding. I ended up giving each female baby the same last name as her dad, and each male baby the same last name as his mom, to avoid that awkward moment when I stop in to the living quarters to see how a couple is doing and find them saying “It’s so nice to spend some time with family….” Dwellers don’t seem to get jealous, and don’t mind in the slightest if their partner from one child hooks up with someone else the next time around. In fact, a few times I’ve sent two or three couples into the larger living areas and have noticed them switching partners repeatedly before they eventually settle down. I’m honestly not sure what causes that.

The app is free and has no ads, which is where the in-app purchases come in. The game uses lunchboxes as its reward system. Each lunchbox has four cards in it, each of which could contain things like caps, guns, outfits, new Dwellers, and so on. You can win lunchboxes in a challenge, but after the game tutorial ends, they’re rare. If you’re impatient, you can spend real money to buy them: $0.99 will get you one box, $3.99 will get you five, $9.99 will get you 15 and $19.99 will get you 40. All those extra caps and items can be handy, but building up your base too quickly can easily overwhelm the delicate balance of power, food and water management and bring your Vault to its knees.

Ultimately, it’s an addictive game, although I admit it does make me feel odd on occasion. My Dwellers are deliriously happy, but are they really, or is that just the face they show me, the Overseer? Sometimes if you zoom in on a room, you’ll catch one Dweller warning another that the Overseer is watching. Dwellers work zealously toward their goals, but once their room reaches it, they slack off and wander around until you come by and collect what they’ve produced, at which point they sprint back to their positions. There’s that breeding thing. Surely not all of them are heterosexual or want to have kids, yet they march off to do their duty and are happy about it. They’ll even head off cheerfully to their deaths in the Wasteland without complaint if you ask them to. Maybe they want to be here, or maybe they understand that being in a Vault is a lot better than being outside it.

Believe me, they are.

I’m going to give it a four out of five stars. There are a couple minor bugs—sometimes pregnant ladies get stuck in the living quarters and you have to close and reopen the game to move them—but on the other hand the game is free. My only recommendation is to get it for your iPad if you have one, since phone screens can be a little tiny. It’s only out for iOS right now, but it should be coming out for other platforms eventually. So even if you’ve never played a Bethesda game before and don’t intend to in the future, go ahead and download it, and try not to let your moral qualms bug you too much.